中文摘要：

光显微镜， X 光检查衍射计，扫描电子显微镜，张力的测试者和动态机械分析器(直接存储器存取) 被使用在微观结构，机械性质和 Mg-3Cu-1Mn (CM31 ) 合金的抑制能力上调查 Y 和 Zn 增加的效果。结果证明随 Y 和 Zn 内容的增加，合金的第二等的树突手臂间距被减少；同时，收益力量被增加。在低紧张振幅，有 Y 和 Zn 增加的合金的抑制能力比 CM31 合金的低。然而，在在 50.01-10 s 上的紧张振幅 ? 1， 250450 瑳的变丑温度范围？

英文摘要：

Optical microscope,X-ray diffractometer,scanning electron microscope,tensile tester and dynamic mechanical analyzer（DMA） were applied to investigate the effects of Y and Zn additions on microstructure,mechanical properties and damping capacity of Mg-3Cu-1Mn（CM31） alloy.The results show that with the increase of Y and Zn contents,the secondary dendrite arm spacing of alloys is reduced;meanwhile,the yield strength is increased.In low strain amplitude,the damping capacity of alloys with Y and Zn addition is lower than that of CM31 alloy.However,in strain amplitude over 5×10-3,the damping capacity of alloy with a trace of Y and Zn addition（1%Y and 2%Zn,mass fraction） increases abnormally with the increase of strain amplitude and is near to that of pure Mg,probably due to the increase of dislocation density caused by the precipitation of secondary phase.The temperature dependence of damping capacity of above alloy was also tested and discussed.